Flexible loop antenna



Jan. 12, 1943. w. J. SCHNELL FLEXIBLE LOOP ANTENNA l Filed 'May e, 1941 Patented Jan. 12, 1943 UNH''ED STATES FLEXIBLE L? ANTENNA Application May 8, 1941, Serial No. 392,480

(Cl. Z50-16) 12 Claims.

This invention relates to radio receiving apparatus and more particularly to portable radio receivers.

A primary object of the invention is the provision of a portable radio receiving apparatus provided with a readily connectible` and disconnectible external loop antenna which may be easily carried in a pocket or the like and is readily and quickly attachable and detachable with respect to a supporting surface such as a window or the like.

A further object is the provision of a flexible loop antenna that is simple and inexpensive in construction, which maybe readily folded and lies substantially llat for carrying in; a pocket or the like, which is readily connected to and disconnected-from a portable radio receiver, and which is quickly and easily attached to and detached from a supporting surface.

A further object is the provision of such exible loop antenna that gives substantially unobstructed clear vision through a Window or the like when. attached thereto.

A further object is the provision of a novel connecting means for readily connecting and disconnecting a exible external loop antenna to and from a radio receiving apparatus.

A further object is the provision of portable radio receiving. apparatus having a built-inV antenna, an external loop antenna adapted for connection tothe receiving apparatus, and novel means for disconnecting the built-in antenna when the external antenna is connected.

These and other objects will be apparent from the following description, the appended claims i and the accompanying drawing in which Fig. 1 is a perspective view of a portablev receiver having an external loop antenna constructed in accordance with the presentinvention connected thereto and attached to a Window of. a vehicle;

Fig. 2 is a perspective View partly broken` away, of the exible loop antenna shown in. Fig.. 1;

Fig. 3 is an enlarged sectional view taken on the line 3 3 of Fig. 2;

Fig.. 4 is an enlarged sectional View taken on the line li-ll of Fig. 2;

Fig. 5 is an enlarged detailed section taken on the line 5-5 of Fig. 2;

Fig. 6 is a fragmentary elevational View showing a portion of the inside of the radio receiving apparatus of Fig. l and illustrating a switch in position therein for disconnecting a built-in antenna when` the flexible loop antenna is connected to the apparatus, the view being taken i illustrated embodiment from the. rear of the front control panel as seen inFig. 1; and

Fig. 7 is a View loo-king upwardly at the switch of Fig. 6 as indicated by the arrow inV Fig. 6 and having the antenna connections' diagrammatically illustrated therein.

Referring to the drawing which illustrates a selected embodiment of the invention and in which like reference characters designate like parts in the several views, there is shown a small, compact', portable radio receiving set lil comprising a housing or casing Il, a control panel I2, a hinged door I3, and a strap i4 providing for ready transportation of the apparatus. A radio receiving apparatus of any desired structure and design is mounted Within the casing il, and an arm l5 of a snap switch extends outwardly through a suitable opening in theside of casing IlI and provides for turning the set on and off. The door, i3, is adapted to be latched shut when the apparatus is not in use to cover the front control panel i2.

To provide for normal reception of radio Waves an antenna 2li is built into the set I0 and in the comprises a spirally wound conductor mounted Within the door I3. The antenna is electrically connected` with the receiving apparatus Within the casing il by means of the door hinges 2l as shown in Fig. 6 of the drawing. Under normal conditions of use, the antenna 2i) provides for receiving radio signals and effecting operation of the set i0.Y

t is often desirable, however, to operate the receiving set It within ay metallic shielding structure, such as an automobile, aeroplane, train and the like, and under such conditions of use the built-in antenna. 2S- is ineffective for proper reception and operation of the set. To provide for proper operation of the receiving apparatus under such conditions of. use, or at any other time that the built-in antenna 2U is ineffectivel for proper reception, an external` flexible loop antenna y is provided and may be readily connected to the set andalso attached to a supporting surface suchA as a window. The loop antenna 25, furthermore, is of such construction that it may be readily folded into a very flatand. compact mass adapted to be easily carried in a pocket or the like and Which whenA attached to a window gives substantially clear unobstructed vision therethrough.

Referring to Figs. 2` and 4 theantenna 25 comprises a plurality of turns of insulated wire 26 arranged side by side and enclosed within inner and. outer bands of relatively thin, Wide, flexible material. 2 and 28. The bands 21 and 28 are of sui'icient width to extend laterally outwardly beyond the turns of wires 2G as indicated at 29 and a suitable adhesive is applied to the inner surfaces of the bands to adhesively secure the bands to the wires 2S and the p-ortion 29 of the bands to each other. rlhe bands 21 and 28 are also preferably stitched together at the portions 25 as indicated at 30, Fig. 4.

The overlying bands 2l and` 23 together with the turns of wire 25 enclosed therein form a relatively thin, band-like loop as shown in Figs. 1

and 2. To provide for readily attaching and de-v taching the loop with respect to a supporting structure such as a window, a nap is sewed or otherwise attached to the loop and is secured as indicated at 35, to a vacuum cup 3?. The arrangement of this flap 35 and vacuum cup 37 with respect to the loop 25 is of primary importance with respect to one feature of the invention.

As clearly shown in Figs. 1 and 2 this arrangement is such that when the vacuum cup 31 is attached to a window or the like, the width of the band-like loop extends substantially normal to the plane of the supporting surface and only the relatively thin side edge of the loop liesY parallel with the window. This thin side edge, furthermore, is in the form of an entirely opened loop. There is thus substantially clear unobstructed vision through the windo-w and the attachment of the antenna does not materially detract from vision through the window.

The turns of wires 26 forming the loop antenna are adapted to be connected to the set lil by a pair of exible lead wires and 4l which are Aconnected to opposite ends of the wires 2E and are enclosed within thin, ribbon-like strips of flexible material 42 similar to the material 27-23. The ribbon-like stripsr 42 preferably have a width corresponding to the width of bands 21 and 28 and are suitably connected to these bands as indicated at 43 in Fig. 2. The inner surfaces of the strips i2 are adhesively secured together as indicated at d to properly enclose the lead wires Mi and M and also to maintain these wires in substantially spaced relationship, as shown in Fig. 3, to reduce the capacity between thein and thereby increase the tuning range. The strips 42 are also preferably stitched together external-ly of the wires 40 and 4| as illustrated at 55, Fig. 3.

The antenna 25 is adapted to be readily connectedto and disconnected 'from the set I0 by means of a pair of plug tips 5B adapted to be received in cooperating sockets provided in the top of the set housing il. As shown in Figs. 2 and 5 the end of the strips i2 remote from the loop 25 are provided with a stifiening member 5I su'ch as ber board, and which is enclosed within the strips by sewing or the like. The plug tips extend outwardly from one side of the stiiening member 5l and are provided with hollow bores 52. A screw 53 having a head 54 extends through the member 5l from the other side thereof and has a threaded portion 55 which is Dress-fitted within the bore 52 of the plug tip 5t. The threaded portion 55 of screw 53 has a slightly larger diameter than the bore 52, and thus by press-fitting the screw into the plug tip bore a very simple, inexpensive and yet rigid and normally undetachable connection is made between theplug tips and the strips d2. To provide van electrical connection between the lead wires 40 and'l and the plug tips E3, the wires are wound around the screws 55 of the respective plug tips and secured beneath the heads 54 of the screws an indicated at 56, Fig. 5.

To provide for proper operation of the radio set lll when the loop antenna 25 is attached thereto, a means is provided for automatically disconnecting the built-in antenna 2B upon insertion of the plug tips 50 within the sockets provided on the top portion of the housing I l This means also provides for operatively connecting the loop antenna with the radio receiving apparatus contained within the housing Il.

As shown in Figs. 6 and 7, this means comprises an elongated base member 60 of suitable insulating material which is attached to a top wall of the housing Il by means of studs 6l and nuts 62. The base 6i) is provided with openings 63 which align with opening E4 provided in the top of the housing Il (see Fig. 6) and are adapted to received the extended reduced end portions 65 of the plug tips 50. 'I he portions 65 of plug tips 50 are adapted to extend downwardly beyond the inner face of the base member 6B and a pair of spring contact clips 66 and 6l are mounted on the insulated base in position to be engaged by the plug tips when inserted through the openings G3 and 64. Each of the contact clips 6B and 61 comprises a substantially U-shapcd member hav ing spring contact iingers 63 extending inwardly and downwardly therefrom. The respective pairs of contact fingers 68 extend relatively close to each other at their lower ends and are provided with curved portion 69 adapted to engage around the plug tip and provide a good electrical connection therewith. The diameter of the portion of the plug tips is also such that the spring fingers 68 are spread somewhat apart upon insertion of the plug tips, thereby insuring a good electrical connection between the plug tipsl and contact clips. Y Y

An electric conducting bracket 'l5 is secured to the base Sii between the contact clips 66 and 61 and supports a leaf spring 16 of electrical conducting material which extends across the tops of the contact clips and tends to bend downwardly into contact therewith. The contact spring I6 thus normally engages and provides an electrical contact with the top of the spring clip 61 as shown in Fig. 7, but is prevented from making electrical contact with the spring clip 66 by a sheet of in suiating material '11 which extends around the clip and over the top thereof between the clip and spring contact member 76. A member 18 attached to the bracket 15 extends across a portion of the top of the contact spring 'M and assists in causing the spring to tend to bend downwardly into contact with the clip 61. A cam. member 8D of suitable insulating material is xedly attached to the end of the spring member 76 adjacent the contact clip 6'1 as indicated at 8| and extends downwardly between the spring arm 63 of the clip. Upon insertion of a plug tip into the contact clip 67, the portion 65 of the plug engages cam member 80 and causes it to lift contact spring out of contacting engagementwith clip member 6T. Upon withdrawal of the plug tip from the clip 61, the contact member 'I6 springs back into contact with the clip 6T.

The operation of this plug receiving and switching means is best described in connection with the wiring connections diagrammatically illustrated in Fig. 7. The wires I'-| and I-2 indicate the input wires which are connected to the built-in antenna 20 by means of hinges 2|. The wire I-I is directly connected to the contact clip G6 while the wire I-Z is connected to the bracket .flat across the width. thereof.

T15 and thus to the contact spring 'i5 by medium of the bracket. The- Wires O-Iand 2A indicate the connections from the plug receiving and switch means to 4the radio apparatus contained within the set housing Il. The wire O is directly connected to the contact clip 66 while the wire 0 2 is directly connected to the contact clip 61. Thus thebuilt-in antenna 20 is normally connected to the receiving apparatus by means of wire I-|, contact clip SG and wire O--I on one side and wire I-2, bracket i5, spring contact member '16, clip 51 and wire O-2 on the' other side. When the plug tips b are inserted in the clips 66 and- 61'", however, to connect the loop antenna 25 to the set, the contact spring 16 is raised out of engagement with clip 61 by means of cam 80, and the built-inaerial is thereby disconnected". At the Sametime the loop antenna is connected to the receiving apparatus' by the electrical contact between the plug tips 50' and clips 66- and 61 to which the wire O--I and 0 2' are connected, a condenser 90 is connected' to the bracket I5 and the contact clip 66.

A portable rad-io receiving set is thus provided that is adapted to operate properly under diiierent and al1 kinds of conditions of use, and an external loop antenna is provided that can be readi-ly and quickly attached to a supporting surface suchas a window of a vehicle and which is si-mply and easily connected to and disconnected from the receiving set The loop antenna, furthermore, is in the form of a relatively thin band having substantially circular shape and mounted on the supporting surface in such manner that the width of the band extends substantially normal to the surface. Vision through the window is thus substantially unimpaired. The construction of the loop antenna is such that4 it is very light in weight and may be readily flattened and folded into la small compact at` mass which can be readily carried in a pocket or' the like. The wires 26 and the adhesively secured enclosing bands 28 and 29 provide suflicient stiffness: and resiliency to hold the loop` open and substantially circular in shape when in, use, whileY permitting attening and folding of the loop when it is desired to carry the same. The band members 28, 29, vand l2Y may also be'water-proofed or otherwise treated to increase the stiffness and maintain the loop and lead-in portion substantially A novel switch means is also provided for disconnecting an antenna built into the setV when the external loop antenna is connected to the receiver.

Changes may be made in the form, construction, and arrangementv of the parts without departing from the spirit of the invention or sacriflcing any of its advantages, and. the right is hereby reserved to make all such changes as fairly fall within the scope of the following claims.

The invention. is hereby claimed as follows;

l. A loop antenna of the character described adapted for ready attachment to.. a window or the like and providing for substantially unobstructed clear vision through said Window or the. like comprising a relatively wide and thin bandlike member forming a circular loop, said member comprising overlying sheets of iiexible material, a plurality of turns of flexible wire en closed in said band-like member, the inner surfaces of said sheets being adhesively secured to said Wires and to each other, a lead-in member extending from the wide flat side of said loop and comprising two overlying portions of relatively wide. and flexible material, av pair` of' flexible lead; wires connected toY said turns: of' wires. and enclosed within said lead-inmember, the innerr surfaces of' said. portions of the leadin member bei-ng adhesively secured together to maintain said l'eadl wires enclosed therein and spaced apart, saidv loop and said lead-in member thereby forming a unitary flexible structure adaptedv to. be arranged in hat position forfolding and the like, plug means connected to said lead Wires andadapted for connection to. aA radio2 rev ceiver atv the end' of said lead-in member, and. suction means connected with said? band-like member for attaching said loop to a windowcr the like with the width of the. band-like'member extending substantially normal to the plane oi the window or the like.

2. A loo-p antenna of thek character described adapted for ready attachment to la window or' the like and providing for: substantially unobstructed` clearA vision through said Window or the like comprising a relatively wide and thin. bandlike member forming a circularloop,.said1 member comprising overlying sheets of flexible; material', ak plurality of turns of flexible wire en'- closed' in said band-like member, the inner surfaces of said. sheets being adhesively secured to said wires and to eachother, said sheets extending laterally outwardly beyond. opposite sides of' said turns of wires, stitching on thev outwardly extendingport'ionsof said sheets to assist in hold-v ing the sheets together and enclosing said turns of wires, a lead-in member extending from the wide flat side of said loop and comprising;l two overlying portions of relatively wide and thin flexible material, a. pair of flexible lead'wires: connected to said turns. of? Wires. and enclosed Within said lead-inmember, the inner surfaces of said portions of the lead-in member being adhesively secured together to maintain said lead wires enclosed therein and spaced apart, said loop and said lead-in member thereby forming. a unitary ilexible structure adapted to be arranged in flat positionl for folding and the like, plug means connected to: said lead wires and adapted for connection tok a radio receiver at the end ofv said lead-in member, and suction means connected with said band-like member for attaching said loop to a Window or the like with the Width of the band-like member extend-ing substantially normal to the plane of the window or the like.

3'. A loop antenna of the character described adapted for ready attachment toa window or the like and providing for substantially unobstructed clear visioni through said windowor the like comprising a relatively wide and thin band-like member forming a circular loop,L said member comprising overlying sheets of flexible material, a plurality of turns of flexible wire enclosed in said' band-like member, the inner surfaces of 'said sheets being adhesively secured to said wires and to each other, said' sheetsy extendingA laterally outwardly beyond opposite sides of l said turnsk of wires, stitching on the outwardly extending portions of said sheets to assist: in holding the sheets together and enclosing said turns of` wires, a lead-V in member extending from the Widey at side' ofV saidV loop and comprising two overlyingv portions of relatively wide and thin iiexiblev material, a pair of flexible lead wiresv connected to said turns of wires and' enclosed within said lead-inmember, the inner surfaces of said portions of the lead-inv member being adhesively secured together to maintain said l'ead wires enclosed therein` and spaced apart, stitching along the side edgesof said lead-in'member and externally of 'saidlead wires to assist in holding said sheet portions together and enclosing the lead wires, said loop and said lead-in member thereby forming a unitary flexible structure adapted to be arranged in fiat position for folding and the like, plug means connected to said lead wires and adapted forconnection to a radio receiver at the end of said lead-in member, and` suction means connected with said band-like member for attaching said loop to a Window or the like with the width of the band-like member extending substantially normal to the plane of the window or the like.

4. A loop antenna of the character described adapted for ready attachment to a window or the like and providing for substantially unobstructed clear vision through said window or the like comprising a relatively wide and thin band-like member forming a circular loop, said member comprising overlying sheets of flexible material, a d

plurality of turns of flexible wire enclosed in said band-like member, the inner surfaces of said sheets being adhesively secured to said wires and toeach other, said sheets extending laterally outwardly beyond opposite sides of said turns of wires, stitching on the outwardly extending portions of said sheets to assist in holding the sheets together and enclosing said turns of wires, a leadin member extending from the wide flat side of said loop and comprising two overlying portions of relatively wide and thin flexible material, a pair of flexible lead wires connected to said turns of wires and enclosed within said lead-in member, the inner surfaces of said portions of the lead-in member beingY adhesively secured together to maintain said lead wires enclosed therein and spaced apart, said lead-in member having substantially the same width as said band-like member to provide for maintaining said leadwires in substantial spaced relationship, said loop and said lead-in member thereby forming a unitary flexible structure adapted to be arranged in flat position for folding and the like, plug means connected to said lead wires and adapted for connection to a radio receiver at the end of said leadin member, and suction means connected with said band-like member for attaching said loop to a window or the like with the width of the bandlike member extending substantially normal to the plane of the window or the like.

5. A loop antenna of the character described adapted for ready attachment to a window or 4the like and providing for substantially unobstructed clear vision through said window or the like comprising a relatively wide and thin band-like mem ber forming a circular loop, a plurality of turns of iiexible wire enclosed in said band-like member, a lead-in member extendingfrom the wide flat side of said loop and comprising two overlying the plane of the window or the like, a reinforcing h member attached to said lead-in member at the end thereof remote from said loop, and apair of plugs receivablewithin a radio receiver attached to said reinforcing member and connected to said lead wires.

6; A loop antenna of the character described adapted for ready attachment to a window or the like and providing for substantially unobstructed clear vision through said window or the like comprising a relatively wide and thin band-like member forming afcircular loop, a plurality of turns of flexible wire enclosed in said band-like member, a lead-in member extending from the wide flat side of said loop and comprising two overlying portions of relatively wide and thin flexible material, a pair of flexible lead wires connected to saidturns of wires and enclosed within said leadin member, said loop and said lead-in member thereby forming a unitary exible structure adapted to be arranged in flat position for folding and the like suction means connected with said band-like member for attaching said loop to a window or the like with the width of the bandlike member extending substantially normal to the plane of the window or the like, a reinforcing member attached to said lead-in member at the end thereof remote from said loop, a pair of plugs receivable within a radio receiver attached to said reinforcing member and connected to said lead wires, each of said plugs comprising a female portion having a hollow bore and receivable on one side of said reinforcing member, and a threaded bolt-like member receivable from the opposite side of said reinforcing member and press-fitted into said hollow bore of the female portion.

7. In an antenna of the character described providing for ready attachment and detachment with respect to a radio receiver, a loop antenna,

, exible lead wires connected to said loop antenna,

means for connecting said lead wires to a radio receiver comprising a reinforcing member, a plug member having a hollow bore and receivable on oneV side of said reinforcing member, and a threaded bolt-like member receivable from the opposite side of said reinforcing member and press-fitted into said hollow bore of the plug member.

8. In a radio receiving apparatus of the character described, a portable radio receiving set, an antenna built into said set, socket means on said set for receiving apair of plugs from an external antenna, clip members in said set for engaging and electrically connecting said plugs to the receiving apparatus, a spring member normally engaging one of said clip members and having electrical contact therewith, an insulated member on said spring member extending into the path of movement of one of said plugs into one of said clip members and providing lfor electrically disconnecting said spring member from said clip member upon insertion of said plug in the said clip member, and an electrical connection between said built-in antenna, said spring member and the other one of said clip members whereby the built-in antenna is normally connected to the receiving apparatus and is disconnected when said external antenna is attached.

9. In a radio receiving apparatus of the character described switch means for disconnecting a built-in antenna and connecting an external antenna, comprising a pair of clip members for receiving plug members on said external antenna and providing for electrically connecting the external antenna to the radio receiving apparatus, a spring member normally engaging one of said clip members and having electrical contact therewith, an insulated member on said spring member extending into the path of movement of one of said plugs into one of said clip members and providing for electrically disconnecting said spring member from said clip member upon insertion of said plug in the said clip member, and an electrical connection between said built-in antenna, said spring member and the other one of said clip members whereby the built-in antenna is normally connected to the receiving apparatus and is disconnected when said external antenna is attached.

10. An antenna comprising a circular strip of material having a plurality of turns of wire enclosed therein to provide a loop antenna, lead-in conductors connected to the free ends of the loop wire and adapted for connection to a radio receiver, said conductors being spaced, an elongated strip of tape material encasing the conductors and connected to the strip enclosing the circular antenna whereby there is provided a single onepiece antenna and lead-in construction having a circular portion at its upper end and an extension lead-in connection, the material encasing the antenna and lead-in being flexible whereby the entire device may be arranged in flat position for folding and the like.

11. An antenna comprising a circular strip of material having a plurality of turns of wire enclosed therein to provide a loop antenna, lead-in conductors connected to the free ends of the loop wire and adapted for connection to a radio receiver, said conductors being spaced, an elongated strip of tape material encasing the conductors and connected to the strip enclosing the circular antenna whereby there is provided a single onepiece antenna and lead-in construction having a circular portion at its upper end and an extension lead-in connection, the material encasing the antenna and lead-in being iiexible whereby the entire device may be arranged in iiat position for folding and the like, and a suction cup attached to said circular strip of material.

12. An antenna comprising a circular strip of material having a plurality of turns of wire enclosed therein to provide a loop antenna, lead-in conductors connected to the free ends of the loop Wire and adapted for connection to a radio receiver, said conductors being spaced, an elongated strip of tape material encasing the conductors and connected to the strip enclosing the circular antenna whereby there is provided a single onepiece antenna and lead-in construction having a circular portion at its upper end and an extension lead-in connection, the material encasing the antenna and lead-in being flexible whereby the entire device may be arranged in flat position for folding and the like, a suction cup attached to said circular strip of material, and plug means carried by said elongated strip of tape material and electrically connected with said lead-in conductors for connecting the antenna to the radio receiver.

WILLIAM J. SCHNELL. 

